1. Field of the Invention
The invention relates generally to improvements in space based cryogenic vessel arrangements and more particularly, but not by way of limitation, to an arrangement for supporting a cold mass within a vacuum vessel from an external frame independently of the vacuum vessel.
2. Description of the Prior Art
In conventionally designed cryogenic vessels, such as helium dewars or superconducting magnet systems, all of the forces exerted on the cold mass, which can be considered to be a helium vessel containing the superconducting apparatus and positioned within a vacuum vessel, are transmitted to the outside magnet or dewar supports through the walls of the vacuum vessel. Thus, the vacuum vessel has to be designed not only to withstand the vacuum generated loads, but also the additional loads of supporting the cold mass.
R. T. Parmley and P. Kittel in their report entitled "System Structural Test Results: Six PODS III Supports", Tenth Int. Cryogenic Engineering Conference, 1CEC10, Butterworth E. Co., VK (1984) disclose the state of the art with passive orbital disconnect strut (PODS) supports for helium dewars intended for space work. They disclose six deformable struts connected from a vacuum shell to the outer surface of the cryogen tank. As the tank diameter changes due to cool down or pressurization, the angled pinned end struts are free to move in and out as the tank moves up or down. A similar adjustment occurs automatically as the vacuum shell changes diameter in orbit due to temperature changes. Thus, the cryogen tank is supported directly from the vacuum shell rather than independently from the external support as in the instant invention.
U.S. Pat. Nos. 4,655,045; 4,606,201 and 4,522,034 are further examples of conventional cryogenic vessels that include an inner vessel containing a superconducting magnet and a freezing liquid of liquid helium or the like. The inner vessel is contained within a vacuum insulating vessel which thermally insulates the inner vessel. The inner vessel is directly supported by a plurality of support members whose outer ends are secured to the vacuum insulating vessel. None of these patents disclose a suspension for the inner vessel which connects directly to the external frame support of the vacuum insulating vessel independently of the insulating vessel.